!§ natural history bulletin. 



Sta. 13, off Havana, 200 fathoms. West Indies, 163 to 

 450 fathoms, (Blake Exp). 



Family, OPHIOTHRICHID^ Ljung. 



OphiothriddcB Ljung., Oph. Viv., 1866. 



Ophiothrichidce Lutken, Addit., Ill, 1869. 



Ophiothrichincp Ljung., Joseph. Exp., 1871. 



The family is characterized by the well defined group of 

 true tooth-papillse; by the absence of mouth-papillae; by the 

 usually numerous, long, slender, generally rough and glassy 

 arm-spines; * and internally by the complex, interlocking ar- 

 ticulations of the arm-bones, and the strong mouth-frames 

 and large radial shields. The peristomial plates, in the typi- 

 cal genera, are in three parts; of these the middle one is large, 

 like an oral shield. The dental plate or apical jaw-plate is a 

 separate piece. 



Nearly all the genera and species of this family live clinging 

 closely to various sponges, gorgonian corals, crinoids, hydroids, 

 or even to other ophiuroids. Many of them are more active 

 in their movements than is usual among Ophiuroidea, and many 

 are bright colored when living. They are mostly found in the 

 warmer seas and in shallow water, and they are most abund- 

 ant and most diversified in the East Indies. Brock enumer- 

 ates fifty-six species of this family from the Indo-Pacific 

 region. Several of the genera are known only from the 

 East Indies or Australia. 



Ophiothrix angulata (Say) Ayres. 



Ophiothrix angulata Ayers, Proc. Bost. Soc. N. Hist., IV, p. 249, 1852. 



Ophiothrix angulata Lyman, 111. Cat. Mus. Comp. Zool., I, p. 162, pi. 

 I, figs. 1-3, 1865; Report Voy. Challenger, Zool., Ophiuroidea, V, 

 pp. 216, 219, 1882; Bull. Mus. Comp. Zool., X, p. 267, 1883. 



Ophiura angulata Say, Journ. Phil. Acad. Nat. Sci., V, p. 145, 1825. 



*The genus Ophiopteron Ludw. is very remarkable for having a broad 

 membranous web between the arm-spines, and appears to be a free- 

 swimming- form. It is from Amboina. 



